1. Field of Invention
The invention relates to a shredder and, in particular, to a shredder that allows its user to control the rotation speed of its motor through a switch, thereby achieving optimal shredding efficiency.
2. Related Art
To prevent documents or data from falling in the hands of unauthorized people, one usually destroys them using a shredder. Therefore, shredders have become an indispensable device for both the office and home.
Currently, shredders are designed to operate at a set, average value of motor torque and rotation speed. Since there is only one rotation speed, it is impossible to find an optimal torque for achieving the best shredding efficiency. In other words, a conventional shredder has only a single rotation speed. If a user wants to shred only one or a few sheets of paper, it is not necessary for the shredder motor to use a great amount of torque. Operating at high torque thus becomes a waste in energy.
In order for a shredder to achieve its optimal efficiency, it is imperative to provide a dual-speed motor that can selectively change its output power. The user can then select a high rotation speed and small torque mode for shredding one or a few sheets of paper, or a low rotation speed and large torque mode for shredding a large amount of paper at one time.